1. Field of the Invention
This invention pertains to a practical, inexpensive, positively acting, improved single control faucet and particularly, to a selectively operative liquid mixing type of faucet whose operating unit is in the form of a cartridge that may be easily replaced.
2. Description of the Prior Art
In an early period, it was customary to provide separate faucets for controlling the flow of water from hot and cold lines. The next development involved the provision of an assembly in which separate operating means would be provided for the hot and cold lines, but the assembly would have a common outlet, in order that a desired mixed temperature, as well as a desired flow of hot or cold water could be supplied as desired. In recent years, the trend has been towards the provision of a faucet unit which not only has a common mixing chamber, but also has a single operating arm or lever for separately controlling the flow of hot and cold water and for providing a desired mixture of the two. Units of this latter type tend to be rather expensive and complicated both in construction and repair. A commonly used type involves the employment of either a solid, cone-like cam or a disc-like cam for separately and simultaneously actuating valve plungers to move them off and on seating positions such that a selective control of water flow may be effected. Valves of this type, in order to be fully positive in their action, have heretofore used spring means for urging individual valves towards a closed or an open position, and have employed cam means to move them towards an opposite position. Such a type of mechanism has entailed considerable wear and tear on the operating parts or elements and, in time, the springs tend to lose their flexibility and to require replacement. The above cam and spring type as well as types using a dual lever system or a tubular, pressure-balanced valve member, all are difficult to repair, thus requiring the services of a skilled person.
There has thus been a need for an improved single operator faucet whose valve elements will be positively actuated in both their closing and opening movements, that will be relatively simple in its construction and maintenance, that will make practical the provision and use of an easily replaceable, inexpensive cartridge operating unit, and that is fully effective in its operation.